A Bibliometric Analysis of Scientific Publications on Cultural-Historical Psychology from 2010 to 2020: Dynamics, Geography, and Key Ideas

Background This paper presents the results of a study into the breadth, dynamics, and diversity of the interdisciplinary branch of cultural-historical psychology. The scatter of thematic areas within the cultural-historical approach indicates the urgent need to continue a systematic and holistic analysis of research related to cultural-historical topics in the context of its various directions and research groups. Design A bibliometric analysis of scientific publications indexed by the Web of Science CC was carried out for the 2010–2020 period . Our previous bibliographic study (Rubtsov et al., 2019) revealed that the number of publications on cultural-historical psychology and citations of them, has recently increased, although unevenly. Results According to our results, the number of publications on cultural-historical psychology is growing unevenly; publications from Russia and the United States made up almost equal shares of the sample, and third place was taken by England, followed by Finland and Sweden. The top 10 journals fell into two subject areas: Psychology and Education and Educational Research. With regard to the geographical location of the publishing houses of the top 10 journals, the highest number was taken by England and Russia. The dominant areas of research were teacher education, university education, and learning activity. Conclusion The most frequently used terms were Vygotsky, activity approach, CHAT, CHP, ZPD, and learning activity.


Introduction
e theoretical and methodological views of L.S. Vygotsky and his closest associates form a signi cant part of the foundation of scienti c discourse and retain great heuristic power in modern psychology. In many ways, Vygotsky's revolutionary thoughts modi ed the ideas about the unit of analysis at di erent stages of the formation of such directions in cultural-historical psychology as the theory of activity (Meshcheryakov & Ponomarev, 2018;Sannino & Engeström, 2018). But the perception of Vygotsky's theory in the international academic communities varies a lot. In his critical analysis Dafermos (2016) noted that there are at least three widespread theoretical frameworks of interpretation of Vygotsky's theory: cognitivism, culturalism, and cultural-historical activity theory. Many researchers emphasize signi cant di erences in the traditions of developing ideas of cultural-historical psychology, in particular, between Russian and non-Russian authors (Bakhurst, 2016;Dafermos, 2016;Miller, 2011).
In modern works, three approaches (paradigms) are o en described, compared, and partially juxtaposed (Ellis, Edwards, & Smagorinsky, 2010, Ch. 1, Introduction): 1) the cultural-historical, which has its roots primarily in Soviet-Russian psychology and philosophy; 2) the social-cultural, associated primarily with a number of famous North American and British psychologists, as well as Spanish authors (Valsiner, & Rosa, 2007, Editors' Introduction); and 3) cultural-historical activity theory (CHAT), which is closely related to the school of activity theory in Helsinki, Finland (Sannino & Engeström, 2018).
Within this framework, it is interesting to look at the scienti c mapping of the spread of Vygotsky's ideas. is can be achieved through bibliometric research methods with focus on visualizing the structure and dynamics of the research eld. We can use statistical methods to identify the outcomes of individuals or research groups, institutions and countries, and national and international networks, and map the development of the eld of cultural-historical psychology. But there is a very small number of such bibliometric studies in the research eld of cultural-historical psychology.
J. Valsiner pioneered measuring the annual frequency of citation of various works of Vygotsky in English-language publications and started with the 1969 to 1984 period. His focus was on analyzing di erences in the citations of Vygotsky's works, but he also recognized that "e orts to popularize Vygotsky's name among English-speaking psychologists have succeeded to a great extent" (Valsiner, 1988, p. 156). W.M. Roth and Y.L. Lee (2007) demonstrated that the 1975-2005 period was marked by an impressive growth in citations and an increase in search results for the keyword "theory of activity. " In terms of speci c research elds, the bibliometric analysis has shown that Vygotsky's ideas represent modern trends in educational research, speci cally the use of dialogic teaching methods (Song et al., 2019), learning English as a second language (Zhang, 2020), creativity and education (Hernández-Torrano, & Ibrayeva, 2020), educational games (Liu et al., 2020), special education, disability, and inclusion (Bal et al., 2020). Another signi cant direction that has shown up in bibliometric analysis is the application of Vygotsky's ideas to the study of human-computer interaction and digital technologies. T. Clemmensen, V. Kaptelinin, and B. Nardi found that there are di erent ways of using, adapting, and developing activity theory for di erent purposes. ey refer to analyzing theory and developing new questions about it; de ning requirements for new tools and supporting empirical analysis; and providing practical recommendations (Clemmensen et al., 2016). Using the bibliometric method, S. Karanasios, B. Nardi, C. Spinuzzi, and J. Malaurent ponted to the role of activity theory in the study of human-technology relations and such digital technologies as social media, smartphones, blockchain, arti cial intelligence, and algorithmic decision-making (Karanasios et al., 2021).
In terms of applying the speci c concepts of the cultural-historical approach, an increase in publications can be also seen; for example, between 2000 and 2019 the number of publications on the "zone of proximal development" (ZPD) grew (Margolis, 2020). A bibliometric mapping analysis of publications from Indonesia for the 2011-2020 period found that the keyword "activity theory" was among the six mostused keywords on the topic of Educational Technology (Darmawansah, 2021).
But it is important to understand that it is not always possible to trace the trajectory of the movement of scienti c ideas, possible dead ends, or breakthrough directions from separate scienti c publications. V. Zaretskii uses the image of a tree as Vygotsky sometimes did to illustrate his ideas. Publications are fruits, or nished products (Zaretskii & Nikolaevskaya, 2019). But can they always be used to reconstruct the process of obtaining them, or to identify the tree on which they grew, or the gardeners who tended them?
We need to look at the interconnections within the scienti c schools. Authorial collaborations in scienti c publications can give us an idea of the invisible colleges of scienti c thought. An invisible college is a group of interacting scholars or scholars who share similar research interests in a subject area, who frequently produce publications related to that subject, and who communicate formally and informally with each other to achieve important goals on the subject, even though they may belong to geographically dispersed research a liates (Zuccala, 2006).

Background
e scatter of thematic areas within the cultural-historical approach indicates the urgent need to continue a systematic and holistic analysis of research related to cultural-historical topics in the broad context of its various directions and research groups.
Our previous bibliographic study (Rubtsov et al., 2019) revealed that the number of publications on cultural-historical psychology and their citations, has recently increased, although unevenly. e study's total sample accounted for 5,669 works (published within 2009-2019 period) and included 1,817 publications from the Web of Science Core Collection and 2,838 from the RSCI database (Russian Science Citation Index). e sample consisted of publications containing the following Author Keywords: cultural-historical psychology (CHP sample) and Vygotsky (Vygotsky sample). e CHP sample embraced 181 publications, which included 161 scienti c articles (88%). Most of these papers were in Russian (87% of the total). e total number of citations in these publications was 457; the h-index of the sample was 12. e Vygotsky sample appeared in 1,636 publications, of which 1,278 (78%) were scienti c articles. Publications in Russian accounted for 10% of the total. e total number of citations for all works in the Vygotsky sample reached 7,850, and the hindex of the sample was 40. Let us look at this sample in greater detail. e Vygotsky sample revealed that most publications included the keywords Activity (436 publications, or 32% of the total number in the sample), Tool (241 or 15%), and Zone of Proximal Development (226 or 14%). e analysis of the representation of publications in the Vygotsky sample by year showed that for Activity, the maximum number of publications was 72 in 2016; for Zone of Proximal Development, 32 and33 (2015 and2017, respectively);and for Tool, 40 publications (2017). e analysis of the geographical distribution of the groups of authors in this sample revealed that the United States had the largest number of publications, with 305 (18.64%), followed by Russia with 221 (13.51%), and Brazil with 162 (9.90%).
Our analysis of the terms used in the titles and abstracts of the publications in the Vygotsky sample identi ed four clusters of terms, which were classi ed by us: Cultural-Historical Psychology (1), Education (2), Development (3),and Zone of Proximal Development (4). Each had a di erent set of links between the terms. In cluster 1, the strongest links were between the following terms: psychology, L.S. Vygotsky, cultural-historical psychology, thinking, consciousness, speech, emotions, art, and personality; in cluster 2, learner/student, teacher, skills, tutor, case analysis, class, application, resource, and mathematics; in cluster 3, young child, parent, motive, early childhood education, self-regulation, family, speech, emotions, art, and literacy; in cluster 4, learner, sca olding, developmental delay, language learning, and dynamic assessment.
In addition, the study presented the citation dynamics of various works and publications of L.S. Vygotsky for the 1999-2019 period based on a sample of 1,014 publications from Google Scholar. e dynamics of the number of citations of Vygotsky's work showed an increase, with the peak in 2017, when it reached 24,226 citations per year. At the beginning of the analyzed period in 1999, a total of 2,724 citations were shown per year; in 2009 it was 12,396, and in 2018 it was 21,078. If we turn to the most cited works, we note that the ve most-cited Vygotsky works included publications in English (two), Portuguese (one), and Russian (two). All the publications were books.

Aim
is study was aimed at analyzing the thematic diversity of publication activity within the framework of the modern branch of cultural-historical psychology in the period from 2010 to 2020, taking into account certain bibliographic variables (year of publication, country, journal, university, and research eld). e following research questions were investigated through bibliometric mapping analysis: RQ1: What were the dynamics of publications in cultural-historical psychology? RQ2: Which countries, organizations, and journals have contributed to culturalhistorical psychology-related research? RQ3: What were the most-used keywords in the abstract sections of journals on cultural-historical psychology from 2010 to 2020? RQ4: What was the semantic similarity of publications in di erent countries, universities, and journals on cultural-historical psychology from 2010 to 2020?

Sample
e Web of Science Core Collection (hereina er WOS CC) was the empirical base of the present study. Web of Science was selected as the scienti c publication source in the study due to it having the largest research database.

Data collection
e study sample consisted of scienti c publications included in the WOS CC for the period of 2010-2020 (see Table 1). Table 1 Sampling of publications in Web of Science Core Collection N Sample Sampling 1 n = 105 Advanced search in the Web of Science Core Collection by the eld AK=Author Keywords: Cultural-historical psychology with speci cation for compliance with the cultural-historical approach. Articles that directly indicate cultural-historical psychology formed the core (core sample records) of the publication for this study. e query formulation in the Web of Science Core Collection advanced search: AK=(("Cultur* Histor* Psychol*") or ("Cultur* Histor* Activ* eor*")) and PY=(2010-2019).
2 n = 526 Analysis of the Web of Science Core Collection citation report, followed by a transition to an array of publications citing core sample records (n=105). Selection of publications that do not belong to the core sample.
3 n = 446 An expert assessment of the sample of publications citing the core with con rmation of the relevance of this sample to the subject of cultural-historical psychology and the activity approach. 4 n = 551 Combination of the core samples with the publications citing the core. us, a combined sample of core+ was obtained. e conducted analysis covered the publications for the 11-year period (2010-2020).
Data analysis e methodology of the present study primarily involved a bibliographic analysis across scienti c publications to test the study hypothesis about the thematic heterogeneity of cultural-historical psychology and the activity approach.
Bibliometric analysis of publications involved the tools of the Web of Science platform. Bibliometric analysis of publications of the core and the core+ was carried out according to the following parameters: year of publication, country, source of publication, scienti c organization, and research eld. e thematic diversity of the content of the core+ sample was analyzed on the basis of the Author Keywords. e Author Keywords are indicated in the articles in the relevant section of the publication. For the analysis, the Author Keywords were used in their original version (without changes). A free so ware VOSviewer v.1.6.13 was used to process the information, received in the Web of Science through co-word analysis of the text, and to visualize the relationships among the Author Keywords. To combine expressions that were close in meaning, a VosViewer esaurus File was used, which takes into account the synonymy of the Author Keywords and uni es the representation of the plural and singular (analysis of co-occurence). When creating a visual map of terms, a threshold for frequency of occurrence was set at 5, which corresponds to 61 keywords ( Figure 2).
For quantitative analysis of the frequency pro les (distributions) of terms, the following mathematical statistical methods were used (SPSS Statistics 23.0): calculation of matrices of linear correlation coe cients r (Pearson product-moment method); and then, for comparison, calculation of distances by formula: d = 10 (1 -r). If d = 0, we can say that the frequency pro les of the terms were completely similar (with r = +1); the possible maximum value is 20 (if r = -1), but in the overwhelming majority of cases, d did not exceed 10 units. Terms are semantic units. e distances were calculated between the frequency distributions of these terms (semantic units). ese distances will be referred to as semantic distances. e use of hierarchical cluster analysis (distances were also estimated on the basis of correlation) made it possible to quantitatively and visually assess the degree of semantic similarity or the distance of the compared samples.
In order to clarify the conclusions based on cluster analysis, factor analysis (principal component analysis) was also carried out by orthogonal Varimax rotation using Kaiser normalization. Here, it should be noted that the described method of analysis did not constitute a variant of co-word analysis (Callon, Courtial, & Laville, 1991), since it was not based on estimates of the strength of links in pairs of keywords cooccurring in publications, and its units of analysis were frequency pro les of terms in specially organized subsamples of publications.

Results and Discussion
e thematic diversity analysis of cultural-historical psychology and activity approach was carried out in two directions: analysis of the frequency distributions of publications in two samples (core and core+) in relation to the year of publication, countries, and journals; and analysis of the thematic diversity of publications related to the core+ sample in relation to the countries, journals, organizations, and scienti c elds.
Frequency distribution analysis RQ1: What were the dynamics of publications in cultural-historical psychology? In order to explore the development of interest in cultural-historical issues in terms of its sporadic or uniform character, we examined how many articles related to the topic were published annually in editions indexed by the Web of Science Core Collection from 2010 onwards. e publication dynamics of the core and core+ samples were evaluated separately. e dynamics of the publication activity of the core+ are presented below (Figure 1). e sporadic nature of publication activity can be identi ed in terms of frequency distribution of core publications by year, with the largest number of publications (24%) appearing in 2018. More broadly, the lowest publication activity is observed from 2011 to 2014 (14%), while the period 2015-2019 accounts for the majority of publications (75%). e nature of the distribution of publications in the core+ sample, including publications of the core and core+ sets, corresponds to the overall pattern of publication and citation in the social sciences: in general, articles started to be actively cited around three to four years a er their publication. In this connection, there was an annual increase in the number of publications constituting the core+ sample: the highest number of publication citations appeared in 2020 (n = 130), while the lowest number was in 2012 (n = 9). e data for 2021 are not included in this analysis since 2021 has not yet ended, and some works are yet to be published. erefore, it can be seen that the number of publications on the cultural-historical psychology is growing unevenly. e annual number of core publications increased by 2.5 times, and the number of core+ by more than eight times. RQ2: Which countries and journals have contributed to cultural-historical psychology related research?
Analysis of the a liation of the authors by sample showed the geographical spread of the cultural-historical approach in terms of the 10 top countries in which the research was carried out. Table 2 demonstrates the frequency distribution of publications in the core+ sample by the authors' country a liations. Almost equal shares of the core+ sample are taken by publications from Russia and the United States (17.42% and 17.24%, respectively). e third place is taken by the group of authors a liated with England (9.44%). Finland and Sweden entered the top 10 in terms of the number of publications in the core+, while Germany and Bulgaria failed to meet the threshold (see Table 2).
It is interesting to look at the speci c academic journals which published works on cultural-historical topic (see Table 3).
Analysis of the periodicals publishing articles of the core+ sample showed that 10 journals were responsible for more than 25% of publications. Among these, the leader in terms of the number of publications was the Cultural-Historical Psychology journal (7.26%); second place was shared by the journals Educational Studies in Mathematics and Issues of Psychology (2.9% each). ird place in terms of the share of publications was taken by the Learning Culture and Social Interaction journal (2.72%). e top 10 journals pertained to two subject areas: Psychology (six journals) and Education & Educational Research ( four journals). ese journals are published by Springer (Netherlands), Taylor & Francis (England), and MSUPE (Russia) (2 journals each). With regard to the geographical location of publishing houses of the top 10 journals, the largest numbers were in England and Russia (four and three journals, respectively). us, in the rst part of the analysis of our research results, we distinguished the groups of countries and academic journals having the largest number of publications in cultural-historical psychology, and determined the yearly frequency of these publications.
RQ3: What were the most-used keywords in the abstract sections in journals on cultural-historical psychology from 2010 to 2020? e frequencies of the representation of Author Keywords in the sample were calculated in order to analyze the content of publications related to cultural-historical psychology. A semantic analysis of the 1,742 words and phrases (author keywords) contained in the sample was carried out. Keywords that were close in meaning were combined; these were those which might di er in singular or plural, presence or absence of articles, spelling errors, or they may contain synonyms. Among the Author Keywords there were unspeci c terms for cultural-historical psychology. By referring in the same publication to terms related to the eld of cultural-historical psychology (CHP) or to the сultural-historical activity theory (CHAT), they showed the intensity of work in a particular eld of cultural-historical research. Semantic analysis resulted in a sample of 1,532 keywords.  Table 4 shows that of the 20 most frequent terms, the rst three places are occupied by: CHP -86 articles; activity approach -55; and CHAT -50. e keywords indicated the following research elds to be prevalent: teacher education, university education, and learning activity. Development, subjectivity, re ection, and identity were among them, as well as speci c terms in cultural-historical psychology -ZPD, perezhivanie, and double stimulation. e representation of the core+ keywords can be visualized using VosViewer tools. e size of a term on the map of keywords below (Fig. 2) is determined by the frequency of the keyword use. e density of keywords placement depends on the number and intensity of links between them. On this keyword map, the lighter the area around a keyword, the higher the frequency of its use. e density of placement of keywords depends on the number and strength of links between them. Unfortunately, not all publications included in the analysis of thematic diversity contained complete bibliographic data (according to the Web of Science Core Collection). For example, Author Keywords might have been missed in some publications. For this reason, our analysis omitted publications in one of the most signi cant scienti c journals, Mind, Culture, and Activity.
Since many of the 1,532 samples were not speci c to a particular scienti c eld, and 78% had a low frequency of occurrence (=1), the next step was to select an abbreviated list of terms for subsequent analysis. e selected Author Keywords were contained in a sample of those articles where "Cultural-historical psychology" and "Cultural-historical activity theory" (that is, core publications) were used among the full list of the Author Keywords. us, the sample consisted of 368 keywords (Shvedovskaya, 2021).
RQ4: What was the semantic similarity of publications on cultural-historical psychology in di erent countries, universities, journals from 2010 to 2020? is study analyzes the semantic distances between di erent samples of publications, di erentiated by a number of variables: country, university, journal, and research eld. Semantic proximity is understood as the distance between frequency distributions of terms in the publications.
Subsequent analysis involved the top 20 most frequently used keywords (see Table 4) to identify the relationship (semantic distances) between the most productive countries (n = 10), organizations (n = 10), sources (n = 10), and subject areas (n = 10) in publications where they were used. Table 5 and Figure 3 present a matrix of the distances between the samples of publications, grouped by country. In total, the analysis included samples from 10 countries in Europe, Australia, and North and South America. e average semantic distance between all countries was 6.98. Table 5 Semantic distances between the samples of publications according to the geographic a liation of the authors, and their distances from the core (CHP_105) and core+ (CHP_551)  As can be seen from Figure 3, the analysis of semantic distances of terms by geographical a liation of the authors showed that the closest to each other were the United States and England (d = 3.24); Russia and Brazil (d = 3.86); and the United States and Canada (d = 3.95) (see Table 5). On the other hand, the greatest distances were between Brazil and Finland (d = 9.73); Russia and Norway (d = 9.72); and Brazil and England (d = 9.40). e dendrogram (Figure 3) obtained for countries with a cut close to the root clearly shows two large clusters. e rst of these clusters includes Russia, Brazil, Australia, and Spain (average d between them = 5.53). e second cluster includes the countries of North America, as well as England and the Scandinavian countries (average d in the second cluster = 6.03). It should be noted that the geographical proximity of countries does not correlate with their thematic proximity. For example, neighboring Scandinavian countries di ered thematically from each other much more markedly than the pair Russia-Brazil or the pair United States-England (see Table 5).
On the other hand, the same dendrogram, cut at a height of 20, depicts a di erentiation of three clusters: the rst remains the same, while the second includes the United States, England, Canada, and Norway (average distance = 4.69), and the third includes publications by Finnish and Swedish authors (distance = 5.92).
In order to con rm the correct selection of clusters, a factor analysis was carried out with a factor loading re nement of less than |0.25|. e analysis con rmed the presence of three components with eigenvalues (Ev) greater than 1: Ev 1 = 4.46; Ev 2 = 1.92; Ev 3 = 1.06. Factor 1 included countries with the following factor loadings: Russia -0.905; Brazil -0.824; Spain -0.610; Australia -0.578; United States -0.287. Factor 2: Australia -0.466; Canada -0.805; United States -0.795; Norway -0.728; England -0.713. e core had factor loadings of 0.864 for factor 1 and 0.352 for factor 2. Factor 3: England -0.430; Finland -0.818; Sweden -0.782. If a country is included in several components, it is assigned to a greater factor loading. Rotation transformed in four iterations.
We note that three terms were common to all groups of countries: activity approach, teacher education, and CHAT (see Table 6). Five more terms common to paired country groupings were CHP, Vygotsky, ZPD, contradictions, and university education. e rst group of countries was responsible for 50.0% of repeated terms, the second group 66.7%, and the third 41.7%. Of course, this indicates a signi cant conceptual overlap with publications in di erent groups of countries. Without even knowing which countries are included in each group, the semantic analysis of the terms indicates that the rst and third groups are associated with the Russian and Finnish schools of thought, respectively. ese are united by three general terms, which are common to all three groups. us, it turns out that the middle group has the greatest number of overlaps with both the Russian school (six) and the Finnish school ( ve), which could be interpreted as its mixed character.   Next, let us consider the distance matrices (see Table 7) and dendrogram (Figure 4) for the samples of publications di erentiated by the authors' a liation to universities. e average distance between all universities was 8.09.
As can be seen from Figure 4, the analysis of the semantic distances of terms according to the authors' a liation to di erent universities showed that the following universities are the closest to each other: Moscow State University of Psychology and Education and Lomonosov Moscow State University (d = 3.36); Monash University and the University of Toronto (d = 4.84); Moscow State University of Psychology and Education and the University of Crete (d = 5.01) (see Table 7). On the other hand, the largest distances were between Lomonosov Moscow State University and the University of Münich  ese results also provide a basis for identifying at least three thematic groups within the analyzed sample of publications. is is consistent with the results of factor analysis with a factor loading re nement of less than |0.25|. e analysis con rmed the presence of three components with eigenvalues (Ev) greater than 1: Ev 1 = 3.70; Ev 2 = 1.35; Ev 3 = 1.05. Factor 1 included organizations with the following factor loadings: Moscow State University of Psychology and Education -0.845; Lomonosov Moscow State University -0.842; the University of Barcelona -0.582; the University of Crete -0.563; Monash University -0.386. Factor 2: the University of Crete -0.459; the University of Toronto -0.853; Monash University -0.728; the University of Manchester -0.464. e core had factor loadings of 0.863 for factor 1 and 0.301 for factor 2. Factor 3: the University of Crete -0.304; the University of Helsinki -0.802; the University of Manchester -0.518; the University of Münich -0.390. If an organization was included in several components, it was assigned to a greater factor loading. Rotation converged in four iterations.
If the university samples of publications are grouped according to the factors having the highest loadings, then the rst group will include two Moscow universities (MSUPE, LMSU) and the universities of Barcelona and Crete, and the second group will comprise the University of Toronto and Monash University, while the third group will be made up of the universities of Helsinki, Manchester and Munich. e thematic diversity and at the same time the overlap of factorized groups of publications, are illustrated in the table of the most frequently used terms in each group (see Table 8). All groups of universities have one common term (Vygotsky), while six terms are common for two groups of universities (CHP, development, ZPD, identity, dialectics, and contradictions).  Table 8 shows that groups of organizations are semantically similar to groups of countries (see Table 6). is is because the parameters "organization" and "country" are related, as they are attributes of the authors of publications in the same sample.
We note that the term Vygotsky was used by all three groups of universities. CHP, Development, and ZPD were included in two groups: "MSUPE, LMSU, Universities of Barcelona and Crete" and "University of Toronto, Monash University. " Activity approach was used by "MSUPE, LMSU, Universities of Barcelona and Crete" and "Universities of Munich, Manchester and Helsinki. " CHAT was used by "University of Toronto, Monash University" and "Universities of Munich, Manchester, and Helsinki. " e remaining terms fell into one group only (see Table 8).
Let us analyze the data on the samples of publications corresponding to di erent journals (see Table 9 and Figure 5). e average distance between all pairs of samples amounted to 8.34. As can be seen from Table 9, the analysis of semantic distances by journals with publications included in the core+ sample showed that the following journals were the closest to each other: Cultural-Historical Psychology and Issues of Psychology (d = 2.84); Cultural-Historical Psychology and Psychological Science and Education  e results of clustering were consistent with the results of factor analysis with a factor loading re nement of less than |0.25|. e analysis con rmed the presence of three components with eigenvalues (Ev) greater than 1: Ev 1 = 3.54; Ev 2 = 1.52; Ev 3 = 1.09. Factor 1 included journals with the following factor loadings: Cultural-Historical Psychology -0.882; Issues of Psychology -0.848; Psychological Science and Education -0.766; Infancia y Aprendizaje -0.528; Factor 2: ZDM Mathematics Education -0.812; Educational Studies in Mathematics -0.770; eory & Psychology -0.389. e core has factor loadings of 0.897 for factor 1 and 0.259 for factor 2. Factor 3: Learning Culture and Social Interaction -0.786; eory & Psychology -0.634; Frontiers in Psychology -0.376. If a journal was included in several components, it was assigned to a greater factor loading. Rotation transformed in four iterations. Table 10 shows the most common terms corresponding to three groups of journals. Two terms were included in all three groups of journals (activity approach, Vygotsky), while ve more terms were common for pairs of groups of journals (ZPD, Development, learning activity, Teacher education, and CHAT). Analysis of the table showing the most frequent terms in these three groups of journals reveals a somewhat similar picture to that of the previous two analyses (for countries and universities): the rst group has four common terms with the second group and three with the third; the second and third groups have three common terms. erefore, we can again highlight the mixed character of the middle group and the di erence in scienti c schools in the rst and third groups.
Finally, let us analyze the data on distances and clusters within the samples of publications, distributed by so-called "subject areas" (see Table 11 and Fig. 6). Here, the average distance between all pairs of samples was 7.87.
As can be seen from Figure 6, the analysis of semantic term distances by the thematic directions to which publications in the Web of Science Core Collection were assigned, showed that the following areas were the closest to each other: Psychology, Multidisciplinary and Psychology, Educational (d = 2.86); Psychology, Educational and Psychology, Developmental (d = 4.43); Psychology, Multidisciplinary and Social Sciences, Interdisciplinary (d = 4.70) (see Table 11). On the other hand, the greatest distances were between Psychology, Developmental and Philosophy (d = 10.15); Linguistics and Philosophy (d = 10.15); Psychology, Clinical and Psychology, Experimental (d = 10.40).
If we cut the dendrogram (Fig. 6) slightly above level 20, we obtain a structure consisting of three clusters. e rst cluster includes six subject areas (average d = 6.32) and a core sample; the second cluster includes three areas (average d = 7.07). ethird cluster includes the thematic area of Philosophy almost equidistantly from the other two clusters (average d from the rst cluster = 9.18; from the second, d = 9.20). e results of factor analysis with a factor loading re nement less than |0.25| provide a basis for identifying a three-factor structure. e analysis con rmed the presence of three components with eigenvalues (Ev) greater than 1: Ev 1 = 4.05; Ev 2 = 1.52; Ev 3 = 1.11. Factor 1 included subject areas with the following factor loadings:   Table 12 shows the most common terms corresponding to the groups of areas, di erentiated by factors. ree terms were common to all areas (Vygotsky,CHAT,Figure 6. Dendrogram for samples of publications pertaining to di erent subject areas and learning activity), while four additional terms combined pairs of groups of areas (CHP, activity approach, university education, and sociocultural theory).
Semantic analysis of the distributions of terms in the three groups of areas (see Table 12) does not reveal a clear ideological commitment to a particular school. Here, the apparent theoretical and methodological confusion between all subject areas is quite understandable since the grouping of samples of publications by subject areas or year was not appropriate for solving our task of determining the diversity of theoretical and methodological approaches. To a greater extent, however, this task correlated with the samples distributed by countries and universities. us, for the correct interpretation of the results, it is essential that not only that all analyses (except for distributions by years) reveal a three-cluster and three-factor structure, but also that the semantic analysis of terms (keywords) is common and distinctive for di erent groups of publications.
In all our terminological comparisons, we can see that some terms are included in all triads of groups or in their pairs (on average, about 20%). e most frequent common terms are Vygotsky, activity approach, CHAT, CHP, ZPD, and learning activity. For this group of six terms, our additional analysis of the dynamics of their use as keywords was not limited to the framework of the sample that served as the basis of our study. Fig. 7 depicts the dynamics of their use over an 11-year period. If we divide this period (2010-2020) into two approximately equal sub-periods, then it is quite clear that the search terms were all used much more o en in the second period than in the rst one. At the same time, the undisputed leader is activity approach (the total number of publications is 1,513, peaking at 197 in 2020), followed by the learning activity (the total number of publications is 667, with the peak at 98 in 2018), and Vygotsky (the total number of publications is 472, max. 61 in 2016). e terms CHAT, CHP, and ZPD are found in less than 60 publications per year. Interestingly, the peak of the ZPD term was in 2011, while the peaks of CHAT and CHP overlap in 2016 and 2018.
C onclusion e present community of active cultural researchers and practitioners was formed about 40 years ago. In this context, we can observe an increase in the number of both its participants and scienti c publications. is growth would have been impossible without a common cultural and historical foundation of ideas, concepts, and theories -not only psychological, but also philosophical, linguistic, semiotic, philological, pedagogical, biological, etc. (Cole, 1996;Cole, 1997;Toomela, 2016;Dafermos, 2016).
In this article, bibliometric analysis was applied to the scienti c output in culturalhistorical psychology. Based on journal publications from 2010 to 2020, we obtained a comprehensive overview of cultural-historical psychology-related research. Hierarchical cluster analysis and factor analysis (Principal Component Analysis) of the publications provided answers to a number of research questions, which we summarize here: RQ1: What were the dynamics of publications in cultural-historical psychology? e number of publications on cultural-historical psychology was established to be growing, although unevenly. e largest number of publications appeared in 2018. e minimum activity was observed from 2011 to 2014, whereas the bulk of publications came in the period from 2015 to 2019. e annual number of core publications increased 2.5 times, and the number of core+ went up more than eight times.
RQ2: Which countries, organizations and journals have contributed to culturalhistorical psychology-related research?
Almost equal shares of the core+ sample were taken by publications from Russia and the United States (17.42% and 17.24%, respectively). ird place was taken by the group of authors a liated with England (9.44%). Finland and Sweden entered the top 10 in terms of the number of publications in the core+, while Germany and Bulgaria remained below the threshhold.
Analysis of periodicals with publications of the core+ showed that more than 25% of the publications appeared in 10 journals. e leader in terms of the number of publications was the journal Cultural-Historical Psychology (7.26%); second place was shared by the journals Educational Studies in Mathematics and Issues of Psychology (Voprosy psikhologii) (2.9% each). ird place was taken by the Learning Culture and Social Interaction journal (2.72%). e top 10 journals pertained to two subject areas -Psychology (six journals) and Education & Educational Research (four journals). ese journals are published by Springer (Netherlands), Taylor & Francis (England), and MSUPE (Russia) (two journals each). With regard to the geographical locations of the publishing houses of the top 10 journals, the bulk were located in England and Russia (four and three journals, respectively).
RQ3: What were the most-used keywords in the abstract section in journals on cultural-historical psychology from 2010 to 2020? e most-used keywords re ected the prevailing areas of research such as teacher education, university education, and learning activity. Development, subjectivity, re ection, and identity were also among them, as well as ones speci c to culturalhistorical psychology -ZPD, perezhivanie, and double stimulation.
RQ4: What was the semantic similarity of publications from 2010 to 2020 in different countries, universities, and journals on cultural-historical psychology?
Analysis of the semantic distances of the publications in the core+ sample by the authors' geographical a liation showed that the following countries were the closest to each other: the United States and England; Russia and Brazil; the United States and Canada. On the other hand, the greatest distances were between Brazil and Finland; Russia and Norway; Brazil and England.
Analysis of the semantic distances between universities showed that the following universities were the closest to each other: Moscow State University of Psychology and Education and Lomonosov Moscow State University; Monash University and the University of Toronto; Moscow State University of Psychology and Education and the University of Crete. On the other hand, the largest distances were between Lomonosov Moscow State University and the University of Münich; the University of Toronto and the University of Helsinki; the University of Barcelona and the University of Helsinki.
Analysis of the semantic distances between the journals showed that the following journals were the closest to each other: Cultural-Historical Psychology and Issues of Psychology; Cultural-Historical Psychology and Psychological Science and Education; Issues of Psychology and Psychological Science and Education. On the other hand, the largest distances were between Cultural-Historical Psychology and ZDM Mathematics Education; ZDM Mathematics Education and Frontiers in Psychology; Infancia y Aprendizaje and ZDM Mathematics Education.
e most frequently used terms in all semantic groups were Vygotsky, activity approach, CHAT, CHP, ZPD, and learning activity. At the same time, the absolute leader was activity approach, followed by learning activity and Vygotsky.
In terms of further research, B.G. Meshcheryakov began work on a chronotope of cultural-historical psychology as a generalized and topological (non-metric) schematic representing the development process, similar to a genealogical tree. e units of chronotope analysis are not versions (varieties) of theory, but larger units -theoretical-methodological paradigms, and scienti c schools somewhat comparable to them (Meshcheryakov, 2021). is study may provide the basis for further research.

Li mitations
To our knowledge, there has been no systematic analysis of the state and evolution of cultural-historical psychology using bibliometric and scientometric methods up to now. e method used in this study could help identify the historical and future development trends of research frontiers in the eld of cultural-historical psychology. However, there are also some limitations in this study that can be overcome in future research.
First, we only collected data from the Web of Science Core Collection Database. Furthermore, in order to get a complete and in-depth analysis, it is preferable to signi cantly expand the analyzed sample of publications. Future studies can extend the search to include other databases such as Scopus.
Second, we did not di erentiate the keywords according to their theoretical and methodological relevance, although it is quite obvious that keywords o en include terms related to the objects of research or intervention (for example, play, education, learning, etc.). In future studies, it is possible to use di erent approaches to the problem of keyword selection in the bibliometric analysis, in particular, the application of the co-word method (Chen and Xiao, 2016). It should be taken into account that the results of a search query in the Web of Science Core Collection Database depend on individual user access restrictions (users may get access to data of di erent time periods).